I certainly wish we had something like that in the UK. Shipping is $28 with USPS and $104 with FedEx!! You can fit the bloody things in an envelope. This is without any import tax too.
If you are afraid of paying shipping for 27+ year old sports car parts, better bail now.
Keeping vintage performance cars running is not cheap, even if the parts are.
Many seals have an industrial cross-over, so call an industrial bearing & seal distributor, and give them the OD, ID, and width, and you may get lucky.
There is at least one shop in the UK that has 7M parts, though I can't think of their name off the top of my head, so search the 'net.
I know, because I have located parts from them.
Shipping by USPS Priority Mail is cheap at $28 for going by air.
As far as customs, we got rid of that problem in 1776....
(hint: have a friend that lives in the US buy all the seals, dunk them in the oldest, slinkiest gear oil they can find, seal them in a bag, seal it in another bag, and ship them as 'used auto parts for warranty evaluation'. Works every time.)
Also, you should look at replacing all the seals at the same time, as they are as old, and have as many miles on them as your cam seals, and you don't want to go through repeated seal changes.